Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

• Question 651:

  Addition of charcoal to the filter bed of sand during water treatment for township supply is to?

  Options:
  A) prevent goiter
  B) prevent tooth decay
  C) remove odour
  D) kill germs
  Show Answer
  The correct answer is C .
• Question 652: 35 cm³ of hydrogen was sparked with 12 cm³ of oxygen at 110°C and 760mm Hg to produce steam. What percentage of the total volume of gas left after the reaction is hydrogen? Options:
  A) 11%
  B) 31%
  C) 35%
  D) 69%
  Show Answer
  The correct answer is B .
• Question 653:

  Which of the following will give a precipitate with an aqueous solution of copper (I) chloride?

  Options:
  A) But-2-ene
  B) But-1-ene
  C) But-2-yne
  D) But-1-yne
  Show Answer
  The correct answer is D .
• Question 654: The solubility in moles per dm³ of 20g of CuSO₄ dissolve in 100 of water at 180°C is?(Cu = 63.5, S = 32, O = 16) Options:
  A) 0.13
  B) 0.25
  C) 1.25
  D) 2.00
  Show Answer
  The correct answer is C .
• Question 655: A metal X forms two bromides with the formulae XBr₂ and XBr₃. What type of bonding exists between X and bromine in the bromide? Options:
  A) Ionic bonding
  B) Metallic bonding
  C) Dative bonding
  D) Covalent bonding
  Show Answer
  The correct answer is A .
• Question 656:

  

  In the diagram above, the mixture of the solids P and Q can be separated by

  Options:
  A) distillation
  B) fractional distillation
  C) crystallization
  D) fractional crystallization
  Show Answer
  The correct answer is C .
• Question 657:

  What volume of 0.100M sodium trioxonitrate (V) solution contains 5g of solute.

  [Na = 23, N = 14, O = 16]

  Options:
  A) 1.7 litres
  B) 0.420 litres
  C) 0.588 litres
  D) 2.35 litres
  Show Answer
  The correct answer is C .
• Question 658: In which of the following reactions can the oxidation number of the nitrogen be said to have increased? Options:
  A) 2NO_(g) + O_2(g) → 2NO_2(g)
  B) NO_(g) + Cl_2(g) → NOCl_2(l)
  C) FeSO_4(aq) + NO_(g) → Fe(NO)SO_4(s)
  D) NO_(g) + Br_2(l) → NOBr_2(l)
  Show Answer
  The correct answer is A .
• Question 659: Electronic configuration of an elements 13x in the subsidiary energy level is Options:
  A) $1s^{2}2s^{2}2p^{6}3s^{2}3p^1$
  B) $1s^{2}2s^{2}2p^{4}3p^{1}3s^1$
  C) $1s^{2}2s^{2}2p^{6}3s^{2}3p^3$
  D) $1s^{1}2s^{2}2p^{6}3s^{2}3p^4$
  Show Answer
  The correct answer is A .
• Question 660:

  N₂O_4(g) ↔ 2NO_2(g) ΔH = +ve

  In the reaction above, an increase in temperature will

  Options:
  A) increase the value of the equilibrium constant
  B) decreases the value of the equilibrium constant
  C) increase in the reactant production
  D) shift the equilibrium to the left
  Show Answer
  The correct answer is A .